When digital content protected by copyright protection (hereinafter, referred to as “copyrighted content” or also simply referred to as “content”) is distributed via a communication network (hereinafter, also simply referred to as “network”), a protocol called digital transmission content protection over Internet protocol (DTCP-IP) is generally used as a copyright protection technology for a network (e.g., Patent Literature 1).
The DTCP-IP is a protocol for transmitting copyrighted content protected by a copyright protection technology such as digital rights management (DRM), and is achieved by applying, to an IP network, a DTCP as a copyright protection technology implemented in a communication standard such as IEEE1394. The DTCP-IP is used for transmitting copyrighted content between devices which are compliant with the guidelines of the digital living network alliance (DLNA) widely used as one of home networks for interconnecting and associating an audio video (AV) device, a personal computer, and other home appliances.